Java - Error en la conexion de SQL Server y Java Netbeans

package javaactividad1;

import java.sql.Connection;

import java.sql.DriverManager;

import javax.swing.JOptionPane;

import java.sql.SQLException;

public class conexion {

    Connection conect = null;

    public Connection conexionSQL(){

        try {

              Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");

              String strconect;

              strconect = "jdbc:sqlserver://localhost:1433;databaseName=master";

              conect = DriverManager.getConnection(strconect,"sa","1234");

              System.out.println("Se conecto a SQL");

        }

        catch(ClassNotFoundException | SQLException e){

            JOptionPane.showMessageDialog(null, "No se puedo conectar a SQL SErver" + e.getMessage(),

                    "Error de conexion", JOptionPane.ERROR_MESSAGE);

        }

        return conect;

    }

}